1. Field of the Invention
The present invention relates to a sandpaper clamp mechanism for use in a finishing tool such as a portable electrically-operated orbital finishing sander which employs a sanding sheet or sandpaper for sanding a workpiece.
2. Prior Art
Finishing tools such as orbital finishing sanders include sandpaper clamps for clamping sanding sheets to platens or pads. One typical sandpaper clamp comprises a spring-clamping device or sandpaper holder which is mounted on a bottom plate and biased by a coil spring for clamping each end of a sanding sheet to a platen or pad. The sandpaper holder includes gripping teeth biased to hold the sanding sheet to the platen under the force of the coil spring disposed around a shaft. To replace the sanding sheet with a new one, a lever attached to the gripping teeth is manually pushed by the user against the bias of the coil spring to turn the sandpaper holder until the gripped end of the sanding sheet is released. Then, a new sanding sheet is placed over the platen and then clamped in position by the sandpaper holder, while the old sanding sheet is being replaced, the lever of the sandpaper holder must be continuously pushed by a finger of one hand and the new sanding sheet must be inserted and held in position between the bottom plate and the gripping teeth by fingers of the other hand. The fingers used during the sanding sheet replacement tend to be tired or get hurt. It is time-consuming and needs skill to replace the old sanding sheet. Sometimes, the new sanding sheet may not be positioned accurately.